Sulfate conjugation is an important pathway in the biotransformation of many neurotransmitters, hormones, drugs and other xenobiotics, and is catalyzed by cytosolic sulfotransferase enzymes designated “SULT.” SULT enzymes are encoded by a gene superfamily, which, in mammals, is divided into two families, SULT1 or phenol SULTs and SULT2 or hydroxysteroid SULTs. The SULT1 and SULT2 families share at least 45% amino acid sequence identity, while members of subfamilies within each family share at least 60% amino acid sequence identity. SULT1 subfamilies include the phenol (1A), thyroid hormone (1B), hydroxyarylamine (1C), and estrogen (1E) SULTs. SULT2 subfamilies include two hydroxysteroid SULTs, 2A1 and 2B1.
Members of the SULT2A subfamily, including SULT2A1, catalyze the sulfate conjugation of hydroxysteroids, such as dehydroepiandrosterone (DHEA). Human SULT2A1 is expressed in the liver, small intestine, and adrenal cortex.